1. Field of the Invention
The present invention relates to a herbicidal composition of a mixture of O-methyl-O-(3-methyl-6-nitrophenyl)-N-secondary-butylphosphorothioamidate (hereinafter referred to as the compound A) or O-ethyl-O-(3-methyl-6-nitrophenyl)-N-secondary-butylphosphorothioamidate (hereinafter referred to as the compound B) and a phenoxy-type herbicide represented by the formula: ##SPC2##
Wherein X represents a chlorine atom or a methyl group, R represents a hydroxy group, a C.sub.1 to C.sub.4 alkoxy group, an amino group or an anilino group, and n represents an integer of 1 to 3; the herbicidal composition displaying a remarkable synergistic effect that any one cannot expect from the single use of each of the components.
2. Description of the Prior Art
One of the various herbicides for rice plant, 2-methyl-4-chlorophenoxyacetate (hereinafter referred to as MCP), has prominent effects to broad-leaved weeds [i.e. monochoria (Monochoria vaginalis Presl), false pimpernel (Lindernia Pyxidaria), tooth cup (Rotala indica Koehne)], but, on the other hand, has a little herbicidal effect to grassy weeds, and moreover has a little herbicidal effect to perennial weeds [i.e. perennial nutsedge sp. (Cyperus serotinus), arrowhead sp. (Sagittaria pygmaea), hardstem bulrush (Scirpus juncoides)].
Each compound A and B has particularly prominent herbicidal activity to grassy weeds [i.e. barnyard grass (Echinochloa Crus-galli)], but has a little herbicidal effect to broad-leaved weeds [i.e. monochoria (Monochoria vaginalis Presl), false pimpernel (Lindernia Pyxidaria), tooth cup (Rotala indica Koehne)] at their large stage, and moreover has a little herbicidal effect to the perennial weeds [i.e. perennial nutsedge sp. (Cyperus serotinus), arrowhead sp. (Sagittaria pygmaea), hardstem bulrush (Scirpus juncoides)].
As the results of extensive studies, present inventors have found that each mixtures containing one of phenoxy-type compounds and the compound A or the compound B have very excellent herbicidal activities to both broad-leaved weeds and to grassy weeds, and particularly each combined herbicides has prominent effects to the perennial weeds which are not controlled by the single use of each of the components, i.e., MCP, the compound A or the compound B.
These facts described above show that present combined herbicides have better advances as a herbicide.